The first time I encountered something this wonderfully simple was on the Acorn Archimedes (RiscOS): an "application" was a folder whose name started with an ex

The first time I encountered something this wonderfully simple was on the Acorn Archimedes (RiscOS): an "application" was a folder whose name started with an exclamation mark. It could customize its icon. If you had the luxury of a hard disk, you could simply drag-and-drop a copy of an application from its floppy disk on which it was distributed.